Single-crystal fiber (SCF) is a fibrous crystalline material, which possesses broad application prospects in the fields of national defense and people's livelihood due to its excellent physical and chemical properties and large aspect ratio. With the maturity and development of the edge-defined film-fed growth technique, laser-heated pedestal growth technique and micro-pulling down technique, SCF ushers in a boom period with various materials and diversified applications. Among them, high melting point oxide SCF for high-temperature sensing has shown great potential for application in harsh environments such as strong oxidation, strong radiation, strong corrosion and strong electromagnetic interference by virtue of its high temperature resistance, oxidation resistance and compact structure. In recent years, researchers have combined optical and acoustic sensing technologies with SCF to broaden the operating temperature of conventional glass fiber sensors while maintaining the structural flexibility, and to compensate for the low lifetime of traditional contact temperature sensing tecniques such as thermocouples in harsh environments. Here, following the development process of the single crystal fiber, the technical characteristics and the research status of the growth techniques as well as the temperature sensing techniques are summarized in detail.